JP2002012983A - Steel sheet coated with composite phosphate film superior in corrosion resistance, lubricity, and coating material adhesiveness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet with a harmonization to an environment, which is superior in a corrosion resistance, a powdering resistance, lubricity, a coating adhesiveness and weldability, and besides does not include chromium. SOLUTION: This steel sheet coated with a composite phosphate film superior in the corrosion resistance, the lubricity, and the coating adhesiveness, is characterized by having a zinc phosphate film layer predominantly composed of tribasic zinc phosphate, and a complex phosphate film on the top of the film layer which is predominantly composed of a phosphate combined with one or more metals selected from the group consisting of Mg, Al, Co, Mn, Ca, and Ni, and a solid lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphatized steel sheet based on a steel sheet used for an automobile body or an electric home appliance, which is excellent in corrosion resistance, lubricity, paint adhesion and chromic acid. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an environment-friendly phosphate composite coated steel sheet that is environmentally friendly because sealing with an aqueous solution is not performed.

[0002]

2. Description of the Related Art Conventionally, as surface treated steel sheets for automobile bodies, electric Zn-Ni alloy coated steel sheets, organic composite coated steel sheets (electric Zn-Ni alloy coated steel sheets + chromate films + organic films), and alloyed hot-dip galvanized steel sheets have been known. Although it is mainly used, in recent years, automobile manufacturers have been studying to use cheaper pure galvanized steel sheets from the viewpoint of cost reduction. However, pure galvanized steel sheet has the problem that the plating layer itself is soft and has a low melting point, so that the plating and the tool are easily welded during press forming, and press cracking and the like are liable to occur in the processing of parts with complicated shapes. The development of materials having excellent properties has been demanded.

Therefore, (1) Japanese Patent Application Laid-Open No. Hei 7-138765 (hereinafter referred to as Prior Art 1) discloses that zinc and phosphorus are formed on a surface of a zinc-containing metal-plated steel sheet at a specific mass ratio and a specific metal content. A zinc phosphate treated steel sheet having a zinc phosphate coating layer containing a specific mass ratio of, and further having a lubricating oil layer thereover has been proposed.

[0004] However, although the zinc phosphate treated steel sheet shown in the prior art 1 has a certain degree of improvement in lubricity, the zinc phosphate coating has a porous coating structure, so that it cannot be used for automobile bodies. Electrodeposition coating did not easily turn around, such as inside the flange or hemming portion, and the corrosion resistance was poor at portions where the steel sheet was likely to be exposed in a bare state even after coating.

As a technique for improving the corrosion resistance of a zinc phosphate-treated steel sheet, a post-treatment called sealing treatment with a chromic acid-based aqueous solution is conventionally performed after zinc phosphate treatment in the field of steel sheets for household appliances. I was However, since the conventional zinc phosphate-treated steel sheet sealing technology contains hexavalent chromium, which is an environmentally regulated substance, it is desired to develop a technology that does not contain chromium, and the following technologies have been proposed.

(2) Japanese Patent Application Laid-Open No. 12-008175 (hereinafter referred to as Prior Art 2) discloses that a zinc-plated steel sheet has a specific zinc phosphate layer on its surface, and further has a magnesium phosphate layer thereon. A surface-treated steel sheet having an amorphous inorganic coating layer made of the same has been proposed.

(3) JP-A-56-136979 (hereinafter referred to as Prior Art 3) discloses that a cold-rolled steel sheet and a galvanized steel sheet are subjected to a phosphate treatment and immediately thereafter contain a chelating agent as a main component. A post-treatment method has been proposed.

(4) JP-A-58-197284 (hereinafter referred to as Prior Art 4) discloses that after a zinc-coated steel sheet is subjected to a phosphate treatment, polyacrylic acid and an aromatic polyhydric alcohol are used. There has been proposed a method for pre-painting a zinc-based plated steel sheet, which is characterized by treating with a zinc-containing steel sheet.

(5) JP-B-63-4916 (hereinafter referred to as Prior Art 5) has a phosphate film of 1-2 g / m ² on a Zn-Ni alloy plating, and further has an upper layer. A highly durable composite plated steel sheet having a polymer film having a thickness of 5 to 10 μm has been proposed.

[0010]

However, the above-mentioned conventional zinc phosphate-treated steel sheets have the following problems, respectively. That is, the surface-treated steel sheet shown in the prior art 2 has relatively good corrosion resistance and paint adhesion, but since the upper layer is formed of an inorganic film composed of only magnesium phosphate, the bead during press molding is formed. The film was easily peeled off by bending and bending back at the part (poor in powdering resistance), and the peeled material deteriorated lubricity, so that press formability was insufficient.

The zinc phosphate treated steel sheets shown in the prior arts 3 and 4 do not have the paint adhesion at the level required as a steel sheet for automobiles because they use a normal zinc phosphate film. In addition, in a surface-treated steel sheet in which an organic sealing is applied to a zinc phosphate film disclosed in these prior arts, an assembly process of an automobile body [shear → press → welding → alkali degreasing → chemical conversion → electrodeposition coating → medium / Overcoat]
In this case, the film was dissolved or deteriorated by contact with an alkali or acid solution, so that the corrosion resistance was poor.

Further, the zinc phosphate treated steel sheet shown in Prior Art 5 uses a normal zinc phosphate film as in Prior Art 3 and 4, and therefore has a paint adhesion level required for a steel sheet for automobiles. It does not have sex. In addition, since the thickness of the organic film formed on the upper layer is extremely large, 5 to 10 μm, not only welding by spot welding is difficult, but also poor powdering resistance, and bending at a bead portion during press forming. Since the peeled material peeled by the return deteriorates the lubricity, the press formability was also poor.

As described above, the conventional techniques cannot satisfy all of corrosion resistance, powdering resistance, lubricity, paint adhesion and weldability. Therefore, the present invention
In view of such problems of the prior art,
An object of the present invention is to provide an environmentally friendly surface-treated steel sheet which is excellent in corrosion resistance, powdering resistance, lubricity, paint adhesion and weldability, and does not contain chromium.

[0014]

The present inventors have conducted intensive studies on the relationship between the coating composition of the phosphate composite coated steel sheet and its corrosion resistance, lubricity, and paint adhesion, and as a result, have found the following. Obtained knowledge. (I) In order to improve corrosion resistance and paint adhesion, after forming a zinc phosphate film on the surface of a steel sheet, a composite phosphate film layer mainly containing a specific phosphate and a solid lubricant is further formed on the surface layer. It is effective to form.

(II) To improve the lubricity, it is effective to incorporate a lubricant into the composite phosphate film. Further, by adjusting the total amount of the zinc phosphate film and the composite phosphate film formed on the surface of the steel sheet to a specific range, the lubricity is further improved, and the zinc phosphate film and the composite phosphate film are further improved. It is preferable that the adhesion amount ratio be in a specific range.

(III) Corrosion resistance and paint adhesion are further improved by adding a rust preventive additive to the composite phosphate film.

The present invention has been made based on such knowledge, and is characterized by having the following configuration. That is, the present invention provides: (1) a zinc phosphate coating layer containing zinc phosphate as a main component on a surface of a zinc-based plated steel sheet;
1 selected from among l, Co, Mn, Ca and Ni
Phosphate composite coating excellent in corrosion resistance, lubricity and paint adhesion characterized by having a composite phosphate film layer mainly composed of a phosphate composed of one or more metals and a solid lubricant. (2) The content of the solid lubricant in the composite phosphate film is 3 to 50 parts by mass with respect to 100 parts by mass of the phosphate in the composite phosphate film in solid content. The phosphate composite coated steel sheet having excellent corrosion resistance, lubricity, and paint adhesion according to (1), (3) the solid lubricant in the composite phosphate film has an average particle diameter of 0.05 to 25 μm. The phosphate composite coated steel sheet according to (1) or (2), which is excellent in corrosion resistance, lubricity, and paint adhesion, characterized by being fine particles of (1) or (2).

(4) The solid lubricant according to any one of (1) to (3), wherein the solid lubricant in the composite phosphate film is polyethylene and / or polytetrafluoroethylene resin. Phosphate composite coated steel sheet with excellent corrosion resistance, lubricity and paint adhesion.

(5) The phosphate in the composite phosphate film contains Mg so that the molar ratio of Mg / P becomes 0.4 / 2 to 1/2. 5) The phosphate composite coated steel sheet according to any one of the above items, which is excellent in corrosion resistance, lubricity, and paint adhesion.

(6) The phosphate in the composite phosphate film contains Al so that the molar ratio of Al / P is 0.3 / 3 to 1/3. 5) The phosphate composite coated steel sheet according to any one of the above items, which is excellent in corrosion resistance, lubricity and paint adhesion.

(7) A rust-preventive additive is contained in the composite phosphate film, and its content is 2 to 50 parts by mass based on 100 parts by mass of the phosphate in the composite phosphate film. The phosphate composite coated steel sheet according to any one of (1) to (6), which is excellent in corrosion resistance, lubricity, and paint adhesion.

(8) Ni, Mn is contained in the zinc phosphate film.
And one or more metals selected from Mg, the total content of which is 0.5 to
The phosphate composite coated steel sheet according to any one of (1) to (7), which is excellent in corrosion resistance, lubricity, and paint adhesion, wherein the content is 8.5% by mass.

(9) The total coating weight of the zinc phosphate coating and the composite phosphate coating is 0.5 to 4 g / m ^2.
The phosphate composite-coated steel sheet according to any one of (1) to (8), which is excellent in corrosion resistance, lubricity, and paint adhesion.

(10) The ratio of the amount of adhesion between the zinc phosphate film and the composite phosphate film is composite phosphate film / zinc phosphate film = 1/100 to 100/100. (1) The phosphate composite coated steel sheet according to any one of (1) to (9), which is excellent in corrosion resistance, lubricity, and paint adhesion.

(11) The phosphate composite coated steel sheet has a rust-preventive oil film layer as the outermost layer, and the amount of the rust-preventive oil film layer is 0.01 to 10 g / m ^2. 1)
The phosphate composite-coated steel sheet excellent in corrosion resistance, lubricity, and paint adhesion according to any one of the above (10) to (10).

Further, the phosphate composite coated steel sheet according to the present invention is excellent not only in corrosion resistance, lubricity and paint adhesion, but also in weldability, and is not environmentally friendly because it is not sealed with a chromic acid aqueous solution. Gentlely its use is extremely useful.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below together with the reasons for limiting the same. As the steel sheet serving as the substrate of the zinc-based plated steel sheet used in the present invention, a cold-rolled steel sheet for general working (C
From Q) to deep drawn cold rolled steel sheet (DQ), high deep drawn cold rolled steel sheet (DDQ), ultra deep drawn cold rolled steel sheet (EDDQ) All high-strength steel sheets ranging from high-strength steel sheets having low mechanical strength levels to general high-tensile steel sheets exceeding 390 MPa, descaled hot-rolled steel sheets, and the like can be used.

As the plating layer of the zinc-based plated steel sheet, for example, Zn plating, Zn—Ni alloy plating (Ni content 1
0-15 mass%), Zn-Fe alloy plating (Fe content 5-25 mass% or 60-90 mass%), Zn-Mn alloy plating (Mn content 30-80 mass%), Zn-Co
Alloy plating (Co content 0.5 to 15% by mass), Zn-
Cr alloy plating (Cr content 5-30% by mass), Zn-
Al alloy plating (Al content: 3 to 60% by mass) is exemplified. In addition, Co, Fe, Ni,
Alloy elements such as Cr, oxides and salts such as silica, alumina, and hardly soluble chromate, and polymers can be blended. Furthermore, it is also possible to form a multilayer plating in which two or more of the same or different plating layers are plated.

As a plating method, an electrolytic method, a melting method,
A known method such as a phase method may be used, but from the viewpoint of corrosion resistance,
Attached amount is 10g / m²So that the plating layer
Preferably, it is formed. Further, in particular, the plating layer is Zn-
Ni alloy plating, Zn-Fe alloy plating, Zn-Mn alloy
Gold plating, Zn-Co alloy plating, Zn-Cr alloy plating
In the case of き, the adhesion amount is 70 g / m²Exceeds powder resistance
Due to poor ring properties, the coating weight is 10-70 g / m
²It is also preferable to have a higher corrosion resistance,
To ensure powdering properties, the coating weight should be 1
5-60g / m ²It is preferable that

The phosphate composite coated steel sheet provided by the present invention comprises a zinc phosphate coating layer mainly composed of zinc phosphate formed on the surface of the zinc-based plated steel sheet, and a zinc phosphate coating layer formed on the zinc phosphate coating layer. And a composite phosphate film layer mainly composed of a phosphate made of a specific metal and a lubricant. However, when the zinc phosphate coating layer, which is the lower layer, has a low adhesion amount, the coating cannot completely cover the surface of the galvanized steel sheet, and there may be exposed portions of the plating. Further, even if the zinc phosphate coating layer has a certain amount of adhesion, the zinc phosphate coating layer itself has a porous coating structure, so that there are not a few plating exposed portions. Therefore, the upper layer of the zinc phosphate film in the present invention includes not only the upper layer of the zinc phosphate film itself but also the upper layer of the plating exposed portion that is not covered with the zinc phosphate film as described above.

The zinc phosphate coating layer formed on the surface of the galvanized steel sheet improves the paint adhesion by the anchor effect, and prevents lubrication by preventing direct contact between the steel sheet and the tool during sliding. It also contributes to the improvement of In the present invention, the zinc phosphate film is not particularly limited as long as it contains zinc phosphate as a main component.
However, when more excellent corrosion resistance, lubricity and paint adhesion are required, Ni, Mn and M
It is preferable to contain one or more metals selected from g. In this case, the content of these metals other than zinc is preferably 0.5 to 8.5% by mass of the zinc phosphate film in total, and particularly when excellent corrosion resistance and paint adhesion are required. 2.5 to 7% by mass
Is more preferable. Further, Ni and Mn and / or
Alternatively, by adding Mg together, the corrosion resistance and paint adhesion are remarkably improved, in which case Ni is preferably 1 to 5.5% by mass, and Mn and Mg are each preferably 0.5 to 4% by mass.

As the zinc phosphate treatment for forming the zinc phosphate coating layer, any method such as a reaction type treatment, a coating type treatment, and an electrolytic type treatment can be used. Specific examples of the reaction-type treatment include first degreasing a steel sheet, washing with water, and then performing surface adjustment, and then forming phosphate ions, nitrate ions,
A zinc phosphate film can be formed by contacting an aqueous solution containing zinc ions as a main component with a treatment liquid to which the following (1) and (2) are added as necessary, washing with water, and drying.

(1) at least one selected from iron ions, nickel ions, manganese ions, cobalt ions, calcium ions and magnesium ions; (2) peroxides, fluoride ions, complex fluoride ions,
At least one selected from nitrite ions The upper layer of the zinc phosphate film is coated with a composite phosphate film mainly composed of a phosphate made of a specific metal and a solid lubricant, thereby providing corrosion resistance and adhesion. Thus, the composite phosphate-coated steel sheet according to the present invention, which satisfies all of lubricity and powdering resistance, can be obtained. Further, by adding a rust preventive additive to the composite phosphate film, corrosion resistance and paint adhesion can be further improved.

Phosphates of a specific metal contained in the composite phosphate film include Mg, Al, Co, Mn, and C.
a phosphate composed of one or more metals selected from a and Ni, and having excellent corrosion resistance, lubricity, and powdering resistance for the first time by containing the phosphate and a solid lubricant. , It is possible to obtain paint adhesion.

In the present invention, the solid lubricant contained in the composite phosphate film is not particularly limited as long as it is a substance capable of imparting lubricity by being added to the film. Things.

(1) Polyolefin resin, paraffin resin: for example, polyethylene, synthetic paraffin, natural paraffin, microwax, chlorinated hydrocarbon, etc. (2) Fluororesin wax: For example, polyfluoroethylene resin (polytetrafluoroethylene) Resins, etc.), polyvinyl fluoride resins, polyvinylidene fluoride resins, etc. (3) Fatty acid amide compounds: for example, stearic acid amide, palmitic acid amide, methylene bis stearamide, ethylene bis stearamide, oleic acid amide,
Esyl amide, alkylene bis fatty acid amide, etc. (1) Metal soaps: for example, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc. (2) Metal sulfides: for example, molybdenum disulfide, tungsten disulfide, etc. (3) Others: For example, graphite, fluorinated graphite, boron nitride and the like.

When particularly excellent lubricity is required among these, it is preferable to mix polyethylene and / or polytetrafluoroethylene resin. In particular, by using a combination of polyethylene and polytetrafluoroethylene resin, more excellent lubricity can be obtained. In the present invention, by setting the content of the solid lubricant to 3 to 50 parts by mass with respect to 100 parts by mass of the phosphate in the composite phosphate film, the lubricating property is further improved. Powdering resistance can be imparted. If the amount of the lubricant is less than 3 parts by mass, the effect of improving lubricity and powdering resistance is not recognized, and if it exceeds 50 parts by mass, paint adhesion, corrosion resistance, and paintability deteriorate. From the viewpoints of paint adhesion, lubricity, corrosion resistance, and paintability, a particularly preferred amount is 10 to 30 parts by mass, and more preferably 15 to 25 parts by mass.

In the present invention, the average particle size of the solid lubricant is not particularly limited, but is preferably 0.05 to 25 μm from the viewpoint of lubricity, powdering resistance and corrosion resistance. When the average particle size is less than 0.05 μm,
Due to the surface concentration of the lubricant, the area occupied by the lubricant in the outermost layer of the organic film increases, thereby deteriorating the paint adhesion. On the other hand, when the average particle diameter exceeds 25 μm, the lubricant does not fall from the organic film, so that a predetermined lubricity cannot be obtained and the corrosion resistance is poor. In order to obtain particularly excellent paint adhesion, corrosion resistance, lubricity, and powdering resistance, the average particle size is 0.1 to 15 μm.
Is preferable, and 0.5 to 10 μm is most preferable.

In the present invention, when the phosphate in the composite zinc phosphate film contains Mg and / or Al among Mg, Al, Co, Mn, Ca and Ni, the corrosion resistance and the paint adhesion are particularly improved. To improve. Especially when the phosphate is Mg
Is preferably contained such that the molar ratio of Mg / P is 0.4 / 2 to 1/2, and the phosphate contains Al and Al /
It is preferable to contain P so that the molar ratio of P becomes 0.3 / 3 to 1/3. A molar ratio of Mg / P of less than 0.4 / 2,
When the molar ratio of Al / P is less than 0.3 / 3, water-soluble precipitates increase in the coating, and the corrosion resistance and the paint adhesion deteriorate.
If the molar ratio of Mg / P is more than 1/2 and the molar ratio of Al / P is more than 1/3, the stability of the processing solution for forming a film is reduced. From the viewpoint of corrosion resistance and paint adhesion, more preferably, the phosphate is Mg and the molar ratio of Mg / P is 0.6 / 2.
To 1/2, most preferably 0.8 / 2 to 1/2. From the same viewpoint, more preferably, the phosphate contains Al, and the molar ratio of Al / P is 0.6 / 3 to 1/1.
3, most preferably 0.8 / 3 to 1/3.

In the present invention, a rust preventive additive can be added to the composite phosphate film as required. The incorporation of a rust inhibitor is effective particularly when excellent corrosion resistance is required. Examples of the rust preventive additive suitable for the present invention include silica, phosphate fine particles, molybdate, phosphomolybdate (eg, aluminum phosphomolybdate), organic phosphoric acid and salts thereof (eg, phytic acid). ,
Phosphonic acids and their metal salts, alkali metal salts, alkaline earth metal salts, etc.), organic inhibitors (eg, hydrazine derivatives, thiol compounds, etc.), and the like. It can be blended in the acid salt film.

In the present invention, among these, silica and phosphate fine particles are preferably blended, and among the silicas, colloidal silica is more preferred from the viewpoint of the stability of the chemical solution. The average particle size of the usable silica is not particularly limited, but is preferably in the range of 5 to 50 nm from the viewpoint of lubricity and powdering resistance.
A more preferred range is 10 to 30 nm. Further, phosphate fine particles that can be suitably used in the present invention are not limited to the phosphate ion skeleton and the degree of condensation, etc.
Any of normal salt, dihydrogen salt, monohydrogen salt and phosphite may be used. Further, the normal salt includes all condensed phosphates such as polyphosphate (eg, zinc phosphate, calcium phosphate, aluminum dihydrogen phosphate, zinc phosphite, etc.) in addition to orthophosphate. Among these, at least one selected from zinc, calcium, and aluminum phosphate fine particles can be more preferably used.
Further, particularly excellent corrosion resistance can be obtained by blending the silica and the phosphate fine particles in combination.

The content of the rust-preventive additive in the composite phosphate coating is preferably 2 to 50 parts by mass based on 100 parts by mass of the phosphate in the composite phosphate coating in solid content. If the amount of the rust-preventive additive is less than 2 parts by mass, the effect of improving corrosion resistance is not sufficient, and if it exceeds 50 parts by mass, paint adhesion and lubricity deteriorate. A particularly preferred content is 5 to 40 parts by mass, more preferably 1 to 40 parts by mass, from the viewpoint of paint adhesion, lubricity, and corrosion resistance.
0 to 30 parts by mass.

In the present invention, various additives other than the above-mentioned solid lubricant and rust-preventive additive can be further compounded as long as they do not adversely affect the quality performance of the galvanized steel sheet. Examples of additives that can be blended include, for example, oxide colloids and / or powders such as alumina, titania and zirconia, and acids and / or salts thereof such as molybdic acid, tungstic acid, vanadic acid and boric acid, zirconium fluoride and silicon fluoride. Fluoride, such as fluoride, titanium fluoride,
Examples include iron phosphide, graphite, conductive fine powders such as antimony-doped tin oxide-coated titanium, antimony-doped indium oxide, carbon black, and metal powder. One or more of these additives are compounded. can do.

The composite phosphate-coated steel sheet according to the present invention has the zinc phosphate coating layer on at least one side of the steel sheet and a composite phosphate coating layer formed on the coating. The total coating weight of the zinc phosphate coating and the composite phosphate coating is preferably 0.5 to 4 g / m ² per one surface of the steel sheet. If the total coating weight is less than 0.5 g / m ² , the corrosion resistance, lubricity, and paint adhesion deteriorate, whereas if it exceeds 4 g / m ² , the amount of powdering increases and lubricity deteriorates. In light of corrosion resistance, lubricity, powdering resistance, and paint adhesion, a more preferable coating amount is 0.7 to 2.5 g / m ² , and most preferably 1.0 to 2.0 g / m ² . .

The method for forming the composite phosphate film is not particularly limited, and can be performed, for example, by the following method. That is, first, the application of the composite phosphate aqueous solution containing the phosphate and the organic resin as the main components to the surface of the zinc phosphate film can be usually performed by a roll coater method. After coating, the coating amount can be adjusted by an air knife method or a roll drawing method. Next, drying is performed using a dryer, a hot air oven, a high frequency induction heating oven, and an infrared oven. Here, the drying temperature is preferably from 50 to 300 ° C. in the reached plate temperature. When the drying temperature is lower than 50 ° C., the film is not sufficiently dried, and the film is sticky, and the film is damaged when the roll is touched after the phosphate treatment, resulting in poor paint adhesion and corrosion resistance. On the other hand, if the drying temperature exceeds 300 ° C., no further effect can be obtained, which is disadvantageous in terms of manufacturing cost. From such a viewpoint, a more preferable drying temperature is 70 to 200 ° C,
More preferably, it is 100 to 150 ° C.

The present invention includes a steel sheet having the above-described coating structure on both sides or one side. Accordingly, aspects of the present invention include, for example, the following. (1) One side ------ Steel sheet surface + Zinc phosphate film + Composite phosphate film One side ------ Steel plate surface + Zinc phosphate film (2) One side ------ Steel plate surface + Zinc phosphate coating + composite phosphate coating One side ------ Steel plate surface (3) Both surfaces ------ Steel plate surface + Zinc phosphate coating + Composite phosphate coating A rust preventive oil layer can be further provided on the upper layer of the acid salt film layer, whereby the corrosion resistance and lubricity can be further improved. Examples of the rust preventive oil include a rust inhibitor (for example, an oil-soluble surfactant), a petroleum base (for example, a mineral oil and a solvent), an oil film conditioner (for example, a mineral oil, a crystalline substance, and a viscous substance), and an oxidant. Examples include ordinary rust-preventive oils, cleaning rust-preventive oils, and lubricating rust-preventive oils, which mainly contain an inhibitor (for example, a phenolic antioxidant) and a lubricant (for example, an extreme pressure additive). Usual rust preventive oils include fingerprint-removable rust preventive oil in which the base is dissolved and decomposed in a petroleum solvent, solvent-diluted rust preventive oil, petrolactam, lubricating oil based rust preventive oil based on wax, And vaporizable rust preventive oils.

The adhesion amount of the rust-preventive oil film is 0.01 to 10
g / m ² is preferred. 0.01g /
effect can not be obtained in which a rust preventive oil film layer is less than m ^2, the adhesion amount is inferior in paint adhesion becomes poor degreasing obtain 10 g / m ^2. In order to obtain more excellent corrosion resistance and paint adhesion, the amount of adhesion is preferably 0.5 to 3 g / m ² . In addition, the phosphate composite coated steel sheet according to the present invention further subjected to a normal zinc phosphate treatment can sufficiently exhibit the effects of the present invention and can be suitably used.

[0048]

Example: Plate thickness 0.7 mm, surface roughness (Ra) 1.0 μm
Was used, and a zinc-based plating was applied thereto to prepare a plated steel sheet. The plated steel sheet was subjected to alkali degreasing and washing with water, subjected to a surface conditioning treatment, and then brought into contact with a zinc phosphate treatment liquid, washed with water and dried to prepare a zinc phosphate treated steel sheet. Next, the coating composition was applied to the zinc phosphate-treated steel sheet by a roll coater, dried without washing with water, and then coated with a rust-preventive oil or a cleaning oil. Lubricity, powdering resistance,
Each test was conducted for corrosion resistance, paint adhesion and weldability. Specific conditions are as shown below.

(1) Plated Steel Sheet Table 1 shows the types of plating and the coating weights of the zinc-based plated steel sheets used in this example.

(2) Zinc Phosphate Treatment The coated steel sheet is degreased and then washed with water to clean the surface, and then the chemical composition of the surface conditioning liquid and zinc phosphate treatment liquid (see Table 2 below), treatment temperature The treatment time was adjusted to prepare zinc phosphate treated steel sheets shown in Table 3 having different amounts of coating and different film compositions. The following is an example of a method for producing a zinc phosphate-treated steel sheet.

[Zinc phosphate treated steel sheet 1] Degreasing (FCL4
480 (manufactured by Nippon Parkerizing Co., Ltd.), 18 g / liter, sprayed at 45 ° C. for 120 seconds, and then washed with water (sprayed for 20 seconds) (A in Table 1)
Then, after the temperature was raised to 50 ° C., it was immersed in a zinc phosphate treatment liquid 1 shown in Table 2 for 10 seconds, washed with water, and dried to obtain a zinc phosphate treated steel sheet 1 shown in Table 3. [Zinc phosphate treated steel sheet 2] Degreasing (FCL4480 (manufactured by Nippon Parkerizing Co., Ltd.), 18 g / l, 45
° C, sprayed for 120 seconds, and then washed (sprayed for 20 seconds) on the plated steel sheet (B in Table 1), surface conditioning treatment (Preparen Z (manufactured by Nippon Parkerizing Co., Ltd.))
(1.5 g / liter, room temperature, sprayed for 2 seconds), immersed in a zinc phosphate treatment solution 2 of Table 2 heated to 45 ° C. for 1 second, washed with water and dried, and phosphoric acid shown in Table 3 A zinc-treated steel sheet 2 was obtained. [Zinc Phosphate Treated Steel Sheet 3] Immersion time in zinc phosphate treated liquid 2 in Table 2 using (C in Table 1) instead of (B in Table 1) for the plated steel sheet of zinc phosphate treated steel sheet 2 The same treatment as that for the zinc phosphate treated steel sheet 2 was performed except that the time was changed to 4 seconds, to obtain a zinc phosphate treated steel sheet 3 shown in Table 3.

[Zinc phosphate treated steel sheet 4] Degreasing (FCL4
480 (manufactured by Nippon Parkerizing Co., Ltd.), 18 g / liter, sprayed at 45 ° C. for 120 seconds, and then washed with water (sprayed for 20 seconds) (B in Table 1).
Was subjected to a surface conditioning treatment (Preparen Z (manufactured by Nippon Parkerizing Co., Ltd.), 1.5 g / liter, room temperature, sprayed for 2 seconds), and the zinc phosphate treatment liquid 3 in Table 2 heated to 60 ° C. Spray treatment for 4 seconds, washing with water and drying were performed to obtain a zinc phosphate treated steel sheet 4 shown in Table 3.

[0053]

[Table 1]

[0054]

[Table 2]

[0055]

[Table 3]

(3) Complex phosphate treatment (3-1) Rust prevention additive Table 4 shows the rust prevention additive (silica) added to the complex phosphate aqueous solution. (3-2) Lubricants Table 5 shows the lubricants added to the aqueous composite phosphate solution. (3-3) Complex phosphate aqueous solution The composition of the complex phosphate treatment aqueous solution is shown in Table 6. In addition, what used the following organic treatment liquid instead of this complex phosphate treatment aqueous solution was made into the comparative example.

Organic treatment liquid 1: oxybenzoic acid aqueous solution 1
/ 100 [mol / liter] Organic treatment liquid 2: 1% aqueous solution of 3-methyl-5-pyrazolone.

(4) Rust preventive oil Table 7 shows the rust preventive oil used in this example. Table 8 shows the evaluation results of the composition, lubricity, powdering resistance, corrosion resistance, and paint adhesion of the phosphate composite coated steel sheet prepared under the above conditions.
Shown in The evaluation method of each characteristic is as follows.

[Lubricity] The pull-out force under the following sliding conditions was measured, and evaluated by friction coefficient = pull-out force / pressure. The evaluation criteria are as follows. (Sliding conditions) Tool contact area: 5 mm x 10 mm Tool material: SKD11 Force: 400 kgf Sliding speed: 1.0 m / min (Evaluation criteria) A: 0.08 or less O: Over 0.08 0.10 or less △ : Over 0.10 0.12 or less ×: Over 0.12

[Powdering resistance] The test material was sheared to a width of 30 mm, the tip radius of the bead: 0.5 mm, the bead height: 4 mm, the pressing force: 500 kgf, and the drawing speed: 2
After a draw bead test was performed at 00 mm / min, the portion of the bead that was slid was peeled off with an adhesive tape, and the amount of plating peeled per unit area before and after the test was measured. The evaluation criteria are as follows.

◎: less than ² ：: ² g / m ² or more and less than 4 g / m ² Δ: 4 g / m ² or more and less than 6 g / m ² ×: 6 g / m ² or more.

[Corrosion Resistance] (1) Non-painting Corrosion Resistance The sample material was degreased (FCL manufactured by Nippon Parkerizing Co., Ltd.).
4460 (immersion at 45 ° C. for 120 seconds), and the end and the back surface were tape-sealed. Then, a corrosion promotion test of the following composite corrosion test cycle was performed, and the degree of red rust after 10 cycles was evaluated. The evaluation criteria are as follows.

(Composite corrosion test cycle) Salt water spray 35 ° C for 2 hours → drying 60 ° C for 4 hours → 95% RH wet 50 ° C for 2 hours (Evaluation criteria) 基準: No red rust generated ○ +: Red rust area ratio less than 25% ○: Red rust area ratio 25% or more and less than 50% △: Red rust area ratio 50% or more and less than 75% ×: Red rust area ratio 75% or more (2) Corrosion resistance after coating After performing a cross cut with a knife and tape-sealing the end and the back surface, a corrosion promotion test of the following composite corrosion test cycle was performed, and evaluation was made based on a swelling width on one side from the cross cut portion after 300 cycles. The evaluation criteria are shown below.

Coating (3 coats) Zinc phosphate treatment: SD6500MZ (standard conditions) Electrocoating: V20, 20 μm thick Intercoat: OTO870 (white color sealer) 35 μm thick Topcoat: OTO647PT (Shast White) 35 μm (Composite corrosion test cycle) Salt spray 10 minutes → dry 155 minutes → wet 75 minutes → dry 160 minutes → wet 80 minutes (Evaluation criteria) 5 mm or more and less than 6 mm ×: 6 mm or more.

[Coating Adhesion] (1) Coating Adhesion 1 After applying the three coatings shown in the following item 1 to the test material, aging the coating material for 24 hours or more after coating, 240 minutes in 50 ° C. ion-exchanged water. After immersion for a period of time, the test piece was taken out, and within 30 minutes immediately after being taken out, the coating film was immersed in a 100 mm square pattern at intervals of 1 mm.
The pieces were cut into pieces, the adhesive tape was adhered and peeled off, and the remaining rate of the coating film was evaluated. The evaluation criteria are shown below. Coating (3 coats) Zinc phosphate treatment: SD6500MZ (standard conditions) Electrodeposition coating: V20 film thickness 20μm Intermediate coating: OTO870 (white color sealer) film thickness 35μm Top coating: OTO647PT (shast white) film thickness 35μm (evaluation) Criteria) ◎: No peeling ○: Peeling rate less than 3% △: Peeling rate 3% or more and less than 10% ×: Peeling rate 10% or more (2) Paint adhesion 2 After degreasing the test piece, use a commercially available paint delicon. 30 μm
After immersing this test piece in boiling water for 4 hours, cut 100 pieces of gobangs at 1 mm intervals on the coating film, extrude 5 mm of Erichsen, and apply adhesive tape to the processed part.
The film was peeled off and evaluated by the residual ratio of the coating film. The evaluation criteria are as follows. (Evaluation criteria) ：: No peeling ○: Peeling rate less than 3% Δ: Peeling rate 3% or more and less than 10% ×: Peeling rate 10% or more.

[Weldability] CF type electrode having a tip diameter of 4.5 mm,
Pressure: 250kgf, Squeeze time: 36 cycles / 6
0 Hz, energization time 14 cycles / 60 Hz, welding current:
A continuous spot test using a mixed spot where the test material and the mild steel sheet were welded 25 points each at the current value immediately before the generation of dust was performed, and the continuous spot property was evaluated. The evaluation criteria are as follows. (Evaluation criteria) ： １: 1500 points or more ○: 1000 points or more and less than 1500 points △: 500 points or more and less than 1000 points ×: less than 500 points

[Table 4]

[0067]

[Table 5]

[0068]

[Table 6]

[0069]

[Table 7]

[0070]

[Table 8]

[0071]

[Table 9]

[0072]

[Table 10]

[0073]

[Table 11]

[0074]

[Table 12]

[0075]

[Table 13]

[0076]

[Table 14]

[0077]

[Table 15]

[0078]

As described above, the phosphate composite coated steel sheet of the present invention exhibits excellent lubricity, powdering resistance and corrosion resistance, and also has excellent paint adhesion and weldability. It is extremely useful as a surface-treated steel sheet for automobiles, home appliances, and building materials.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C10M 103/06 C10M 103/06 D 4K062 107/04 107/04 107/38 107/38 125/24 125 / 24 125/26 125/26 173/02 173/02 C23C 22/12 C23C 22/12 28/00 28/00 C C23F 11/00 C23F 11/00 B // C10N 10:04 C10N 10:04 10:06 10:06 10:14 10:14 10:16 10:16 20:06 20:06 Z 30:12 30:12 50:02 50:02 50:08 50:08 80:00 80:00 (72) Invention Person Takahiro Kubota 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan Inside Nihon Kokan Co., Ltd. (72) Inventor Masaaki Yamashita 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan, F-term (reference) 4D075 AE03 BB75X CA09 CA13 CA33 DA06 DB05 DC12 EA02 EB01 EB13 EB16 EC15 EC24 EC53 EC54 4F100 AA04C AA04D AB03A AB09D AB10D AB15D AB16D A B18B AJ11E AK04D AK18D AS00E BA04 BA05 BA07 CA14D CA19D DE01D EH71B GB32. CA18 CA23 CA28 CA29 CA32 CA39 CA41 DA15 DA16 EB02 EB05 EB08 4K044 AA02 AB02 BA10 BA17 BA21 BB04 BB05 BC01 BC02 BC04 BC08 CA11 CA18 CA53 CA64 4K062 AA01 BB09 BC01 BC30 FA12 FA16 GA10

Claims (11)

[Claims] 1. A zinc phosphate coating layer containing zinc phosphate as a main component on a surface of a zinc-based plated steel sheet, and M
g, Al, Co, Mn, Ca and Ni, characterized by having a composite phosphate film layer mainly composed of a phosphate made of one or two or more metals and a solid lubricant. Phosphate composite coated steel sheet with excellent corrosion resistance, lubricity and paint adhesion. 2. The method according to claim 1, wherein the content of the solid lubricant in the composite phosphate film is a solid content of phosphate 1 in the composite phosphate film.
2. The phosphate composite coated steel sheet according to claim 1, which is 3 to 50 parts by mass with respect to 00 parts by mass. 3. The corrosion resistance, lubricity and paint adhesion according to claim 1 or 2, wherein the solid lubricant in the composite phosphate film is fine particles having an average particle diameter of 0.05 to 25 μm. Excellent phosphate composite coated steel sheet. The corrosion resistance and lubrication according to any one of claims 1 to 3, wherein the solid lubricant in the composite phosphate film is polyethylene and / or polytetrafluoroethylene resin. Phosphate-coated steel sheet with excellent properties and paint adhesion. 5. The phosphate in the composite phosphate film is M
g, so that the molar ratio of Mg / P is 0.4 / 2 to 1/2, wherein the corrosion resistance, lubricity, and paint adhesion are as described in any one of claims 1 to 4. Phosphate composite coated steel sheet with excellent resistance. 6. The phosphate in the composite phosphate film is A
1 is contained so that the molar ratio of Al / P becomes 0.3 / 3 to 1/3, and the corrosion resistance, lubricity, and paint adhesion of any one of claims 1 to 5 are characterized. Phosphate composite coated steel sheet with excellent resistance. 7. The composite phosphate coating further contains a rust-preventive additive, the content of which is 2 to 50 parts by mass based on 100 parts by mass of phosphate in the composite phosphate coating. The phosphate composite coated steel sheet according to any one of claims 1 to 6, which is excellent in corrosion resistance, lubricity, and paint adhesion. 8. The zinc phosphate film contains one or more metals selected from Ni, Mn and Mg, and the total content of the metal is 0.5 to 8%. .5
The phosphate composite coated steel sheet according to any one of claims 1 to 7, which is excellent in corrosion resistance, lubricity, and paint adhesion. 9. The method according to claim 1, wherein the total coating weight of the zinc phosphate coating and the composite phosphate coating is 0.5 to 4 g / m ^2. A phosphate composite coated steel sheet having excellent corrosion resistance, lubricity and paint adhesion as described. 10. The method according to claim 1, wherein the ratio of the amount of adhesion between the zinc phosphate film and the composite phosphate film is composite phosphate film / zinc phosphate film = 1/100 to 100/100. Item 10. A phosphate composite-coated steel sheet having excellent corrosion resistance, lubricity, and paint adhesion according to any one of Items 1 to 9. 11. The phosphate composite coated steel sheet has a rust-preventive oil film layer as the outermost layer, and the amount of the rust-preventive oil film layer is 0.0
The weight is 1 to 10 g / m ^2.
0. The phosphate composite coated steel sheet according to any one of 0, which is excellent in corrosion resistance, lubricity, and paint adhesion.